结构数组 CLI

发布于 2024-08-27 10:39:39 字数 695 浏览 7 评论 0原文

public value struct ListOfWindows
{
 HWND hWindow;
 int winID;
 String^ capName;
};

这就是我的结构，现在我已经创建了它们的数组：

array<ListOfWindows ^> ^ MyArray =  gcnew array<ListOfWindows ^>(5);

现在为了测试它是否有效，我做了一个简单的函数：

void AddStruct( )
{
  HWND temp = ::FindWindow( NULL, "Test" );
  if( temp == NULL ) return;
  MyArray[0]->hWindow = temp; // debug time error..

  return;
}

错误：Window.exe 中发生了类型为“System.NullReferenceException”的未处理异常

Additional information: Object reference not set to an instance of an object.

不知道该怎么办..对 CLI 有点陌生，所以如果你能帮忙，请做.. 谢谢。

原文

public value struct ListOfWindows
{
 HWND hWindow;
 int winID;
 String^ capName;
};

thats my structure now i have created an array of them:

array<ListOfWindows ^> ^ MyArray =  gcnew array<ListOfWindows ^>(5);

now to test if that works i made a simple function:

void AddStruct( )
{
  HWND temp = ::FindWindow( NULL, "Test" );
  if( temp == NULL ) return;
  MyArray[0]->hWindow = temp; // debug time error..

  return;
}

ERROR: An unhandled exception of type 'System.NullReferenceException' occurred in Window.exe

Additional information: Object reference not set to an instance of an object.

dont know what to do.. kinda new to CLI so if you can help please do..
Thanks.

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机场等船 2024-09-03 10:39:39

好吧，您有一个对象引用数组，但我没有看到任何实际将对象放入其中的任何代码。在访问 MyArray[0] 之前，您可能想将一个对象放入数组的位置 0 处。

我会将 ListOfWindows 更改为引用类 - 在您的上下文中它不会将它用作值类没有多大意义 - 然后您可以将一个对象添加到数组中，如下所示：（

MyArray[0] = gcnew ListOfWindows;

未经测试，但这或多或少是它应该如何工作的）。一旦您实际添加了该对象，您就可以与它进行交互。

Well, you have an array of references to objects but I don't see any code that actually puts an object into any of them. Before accessing MyArray[0] you might want to put an object into the array at position 0.

I would change ListOfWindows to be a ref class - in your context it doesn't make much sense to use it as a value class - and then you can add an object to the array like this:

MyArray[0] = gcnew ListOfWindows;

(Untested but that's more or less how it should work). Once you've actually added that object you can then interact with it.

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三生一梦 2024-09-03 10:39:39

首先，您要创建一个引用数组，而不是一个值数组，因此正如 @timo-geusch 所说，您需要在创建引用数组后创建这些对象。

但是，您也可以创建这样的值数组。

array<ListOfWindows>^ MyArray =  gcnew array<ListOfWindows>(5);

然后您可以使用 .运算符而不是 ->运算符，像这样。

void AddStruct( )
{
    HWND temp = ::FindWindow( NULL, "Test" );
    if( temp == NULL ) return;
    MyArray[0].hWindow = temp; // << here you access the value type, not the reference
    return;
}

希望有帮助

First you're creating an array of references not an array of values, so as @timo-geusch says you need to create those objects after creating your array of references.

However you could also create an array of values like this.

array<ListOfWindows>^ MyArray =  gcnew array<ListOfWindows>(5);

Then you'd access those values with the . operator instead of -> operator, like this.

void AddStruct( )
{
    HWND temp = ::FindWindow( NULL, "Test" );
    if( temp == NULL ) return;
    MyArray[0].hWindow = temp; // << here you access the value type, not the reference
    return;
}

Hope that helps

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